This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | -1 |
| 8 | -7 |
| 9 | -23 |
| 10 | -59 |
| 11 | -139 |
| 12 | -311 |
| 13 | -677 |
| 14 | -1443 |
| 15 | -3031 |
| 16 | -6295 |
| 17 | -12967 |
| 18 | -26543 |
| 19 | -54073 |
| 20 | -109743 |
| 21 | -222071 |
| 22 | -448323 |
| 23 | -903411 |
| 24 | -1817767 |
| 25 | -3653245 |
| 26 | -7335147 |
| 27 | -14716663 |
| 28 | -29508351 |
| 29 | -59138095 |
| 30 | -118472607 |